wc -l medals.txt
grep -E "(中国|中国香港|中国台北)" medals.txt | sort -t ' ' -k 5,5nr
awk '{print $1, $4}' medals.txt | sort -k2,2nr | head -n 5 | awk '{print $1}'
sort -t',' -k2,2nr medals.txt | head -n 5 | tee >(awk -F',' '{print "第"NR"名:", $1, "金牌:", $2}') >(awk -F',' '{sum += $2} END {print "前五名金牌总数:", sum}') >/dev/null

